The following background information may present examples of specific aspects of the prior art (e.g., without limitation, approaches, facts, or common wisdom) that, while expected to be helpful to further educate the reader as to additional aspects of the prior art, is not to be construed as limiting the present invention, or any embodiments thereof, to anything stated or implied therein or inferred thereupon.
It is known that a jack-up mobile drilling unit is a rig that can be jacked up above the sea using legs that can be lowered, much like jacks. These rigs are typically used in water depths up to 390 feet, although some designs can go to 560 feet depth. They are designed to move from place to place, and then anchor themselves by deploying the legs to the ocean bottom using a rack and pinion gear system on each leg. Of course these types of jack-up rigs cannot be used in ice infested waters, as the floating ice may get entangled in between the legs and jeopardize the stability of the rig.
Structures with conical base are efficient in resisting lateral ice forces; however, examples of some specific conical structures in the prior art showed that these structures have serious stability problems during floatation and transit. Moreover, these structures could not cover a wide range of water depths.
In view of the foregoing, it is clear that these traditional techniques are not perfect and leave room for more optimal approaches.
Unless otherwise indicated illustrations in the figures are not necessarily drawn to scale.